/Engine/Plugins/Experimental/PCG/Source/PCG/Public/Metadata/PCGMetadata.h
Creates missing attribute from another metadata if it is not currently present - note that this does not copy values
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category="PCG|Metadata") void AddAttribute ( const [UPCGMetadata](API\Plugins\PCG\Metadata\UPCGMetadata) * InOther, [FName](API\Runtime\Core\UObject\FName) AttributeName )